Railroad flat cars are commonly known as modified and adapted to carry automotive vehicles by using prefabricated racks which enable two or more levels of vehicles to be carried on each flat car.
Normally these racks are made of an open I-beam construction to provide a basic framework with vertical members provided at spaced intervals along opposite sides of the flat car and with cross members therebetween for supporting channel members open upwardly to serve as a driveway and support for the cars, vans, small trucks and other vehicles that are carried.
Until recently, no cover or side wall protection was considered necessary for these carrier racks since all of the vehicles are built to withstand the elements and they can all be securely locked. However, growing incidents of vandalism now make it appear necessary that some form of side wall protection be provided.
Most proposals are for some form of panel or curtain wall protection that will span several of the vertical members and be fastened thereto. However, the protective panels themselves are subject to damage and need to be replaceable. which in turn requires that they be relatively inexpensive, easy to stock and to handle, and that they be readily replaceable, if possible, without requiring that a railroad car be taken out of service while repairs are being made.
Considerations are also due, in providing these protective side walls, as regards how to securely retain them and still allow some flexing over a span of any length, since this is an inherent problem with railroad cars of any appreciable length subject as they are to the irregularities in the lay of railroad tracks.
Still another problem is to prevent the protective panels from rubbing or wearing together, or against other structural members, and causing undue noise and racket.
What is needed is a protective panel wall system which is readily adaptable for use with different open framework carrier racks, makes use of relatively standardized panel lengths, allows for limited lateral flexing, provides means for securing and positively retaining the panels, but allows for their repair or replacement with reasonable ease and expediency.